​Feeding By Flatulence?

The Story of the Bassian Thrush!

The Bassian Thrush (Zoothera lunulata) is a wonderful little bird, endemic to Australia and found along most of the east coast. An inmate specialist of dense forest, wet scrub, and gullies, the bird spends its days frolicking about the leaf-litter, shielded overhead by a thick carpet of protective canopy. They are an alluring deep green, with brown mottling and scalloping across their back, rump, and head. Their underneath is paler but also decorated with the same handsome scalloping as on the upperparts. This varied and attractive plumage has given the species such nicknames as the Olive-tailed Thrush, Ground Thrush, and Scaly Thrush.

Despite their superb appeal, the Bassian Thrush has a secret and a rather amusing one at that. This little secret was seemingly so clandestine that I had not encountered it prior in any of my readings. In fact, its divulgence came to me from a rather unlikely source. In form of an online piece of text, that set to explain a number of rather bizarre and peculiar birding anomalies, I read that the humble Bassian Thrush hunts by use of flatulence. Yes, you read that correctly.

I imagine you have the same amount of surprise etched across your face as I did mine, when upon first reading that articles title. Naturally, I was a little dismissive of such a unique fact presented by the "Top 10 Completely Bizarre Bird Facts" article online. After probing through some further literature and the wide world web, it was proving to be rather difficult to find any evidence either for or against. It was seeming that this soft-spoken member of the Turdidae family does, in fact, have a few secrets to tell. So it was time to venture a little further...

Equally amused and intrigued, I ventured out into the field in hope of finding one of these little fellas at work. I hoped to catch one in the act of feeding, wherein I may hopefully learn a little more about this strange phenomenon. In the meantime, I read up a little more on our unexpected friend. According to these online resources, the Bassian Thrush uses it's uncanny ability to force its feed from the ground. It sprays a thick stream of flatulence around an area it's probing for worms. The gas then provokes a response from the worms (who surprisingly have an extraordinary complex smelling system, though are mainly driven by electrical stimulants), who then, in turn, react to the odour, allegedly making it easier for the Thrush to then swoop down and isolate its prey.

​Personally, I remained unconvinced. The whole thing seeming a little farfetched. So I decided to approach solving this mystery from another angle. Perhaps an angle a little closer to the ground in fact? It was time to analyse the worms...

Worldwide, there are approximately 6,000 species of earthworms that belong to 20 families, eight of which are represented in Australia. They are found in soils usually close to damp and/or dark areas such as leaf litter, below stones and occasionally even in trees or arboreal mosses. But here's where it gets really interesting, worms don't have lungs. So how could they breathe in the traditional sense that a human can? Well they do in fact need oxygen, and being lungless, they instead absorb it through tiny pores in their skin which is found all over their bodies. So if the worms can't breathe (or taste for that matter) an airborne excretion allegedly performed by the Bassian Thrush, then how could they be affected by the so-described flatulence?

Worm thoughts aside, I did, in fact, manage to track down a rather companionable Bassian Thrush without too much trouble. I observed it feeding, singing and flickering amongst the dense, mossy leaf-litter of the emerald forest floor. However, in all this time, I did not receive the privilege of the fabled aforementioned feeding technique I had come to search for. Undeterred, I snapped some shots (on my brand new Canon 7dii camera) and soon left the thrush in peace.

With the worm facts now on the table, as well as a healthy dosing of anecdotal Turdidae facts, it seems we can debunk this all as a rather amusing farce on flatulence. There seems to be no scientific proof and or study to this myth. A paper published in the 2016 AFO on Bassian Thrush, in fact, discussed feeding in great detail but has no mention of the idea of feeding by flatulence. So with that, I'm happy to call it, as Mr. Trump put it so, as Fake News! Until next time, I'd be careful about what you read on "Top 10 Completely Bizarre Bird Facts" - but we'll have to check the remaining 9 in some separate blog posts!

Article hating aside, Bassian Thrush are curious and novel avian treasures of Australia. Their behaviours, songs, exquisite plumage and habitats seem reason enough to me why we should do our very best to observe them, conserve them and continue to wonder at their unimaginable differentness.

PS. Don't forget to leave a comment? Why do you love the Bassian Thrush? Have you ever seen it perform this behaviour?

James Mustafa is a birder, wildlife enthusiast and self-confessed twitcher from Melbourne, Australia. A musician and composer by trade, he has been birding, exploring nature and appreciate wildlife for all his life. Since taking up a fascinating with birds, he has soared with tropicbirds in the Indian Ocean, chased owls in North America, danced with kiwi in New Zealand and twitched everything from gulls to leaf warblers across Australia.